how to assign linkbutton name in gridview

Question

I'm getting object reference error.. 

my code is :

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)

{

if (e.Row.RowType == DataControlRowType.DataRow)

{

foreach (GridViewRow r in GridView1.Rows)

{

LinkButton lbl = (LinkButton)r.Cells[1].FindControl("LinkButton1");

//LinkButton lbl = (LinkButton)e.Row.FindControl("LinkButton1") as LinkButton; 

string str = r.Cells[0].Text;

string str1 = str.Substring(0, str.IndexOf("(")).Trim();

if (str1 == "Abnormal")

{

con.Open();

cmd = new OracleCommand("", con);

dr = cmd.ExecuteReader();

while (dr.Read())

{

lbl.Text = dr[0].ToString();

//r.Cells[1].Text = dr[0].ToString();

}

con.Close();

}

else if (str1 == "Sub-Normal")

{

con.Open();

cmd = new OracleCommand(" ", con);

dr = cmd.ExecuteReader();

while (dr.Read())

{

lbl.Text = dr[0].ToString(); 

//r.Cells[1].Text = dr[0].ToString();

}

con.Close();

}

else if (str1 == "Normal")

{

con.Open();

cmd = new OracleCommand("", con);

dr = cmd.ExecuteReader();

while (dr.Read())

{

lbl.Text = dr[0].ToString(); 

//r.Cells[1].Text = dr[0].ToString();

}

con.Close();

}

else if (str1 == "Critical")

{

con.Open();

cmd = new OracleCommand("", con);

dr = cmd.ExecuteReader();

while (dr.Read())

{

lbl.Text = dr[0].ToString(); 

//r.Cells[1].Text = dr[0].ToString();

}

con.Close();

}

else if (str1 == "Super Critical")

{

con.Open();

cmd = new OracleCommand("", con);

dr = cmd.ExecuteReader();

while (dr.Read())

{

lbl.Text = dr[0].ToString(); 

//r.Cells[1].Text = dr[0].ToString();

}

con.Close();

}

}

 

} 

}

 

Thanks in advanced.